Thin film magnetic head and method of manufacturing same

ABSTRACT

A thin film magnetic head capable of shortening a manufacturing time and a method of manufacturing the same are provided. After forming a write gap layer by using a non-magnetic conductive material such as copper, a top pole is formed on the write gap layer by growing a plating film with the write gap layer used as a seed layer. Unlike the case where the write gap layer is formed by using a non-magnetic insulating material such as alumina, a step of newly forming a seed layer aside from the write gap layer and a step of selectively removing the newly formed seed layer become unnecessary. Therefore, the number of manufacturing processes is reduced, and the manufacturing time of the thin film magnetic head is shortened.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a thin film magnetic head havingan inductive magnetic transducer for writing and a method ofmanufacturing the same.

[0003] 2. Description of the Related Art

[0004] In recent years, an improvement in performance of a thin filmmagnetic head is demanded in accordance with an increase in arealdensity of a hard disk drive. As a thin film magnetic head, for example,a composite thin film magnetic head in which a recording head having aninductive magnetic transducer for writing and a reproducing head havinga magnetoresistive (hereinbelow, referred to as MR) element for readingare laminated is widely used.

[0005] The recording head, for example, comprises: a top pole and abottom pole which are disposed on the top of, and on the bottom of awrite gap, respectively, while sandwiching the write gap made of anon-magnetic insulating material such as aluminum oxide (Al₂O₃;hereinbelow, simply called “alumina”); a coil for generating themagnetic flux which is disposed in a space between the top pole and thebottom pole; and an insulating layer for embedding the coil in the spacebetween the top pole and the bottom pole. Each of the top pole and thebottom pole has a uniform width which is almost the same as each otherin the vicinity of the write gap in a region on a side close to arecording medium facing surface (air bearing surface) facing a magneticrecording medium (hereinbelow, simply called “recording medium”),thereby a trim structure which specifies a recording track width isconstructed. For example, after forming the top pole including a portion(hereinbelow, simply called “uniform width portion”) having the uniformwidth for defining the recording track width of the recording medium, byusing the uniform width portion as a mask, the write gap and the bottompole are etched in a self-aligned manner, and thereby the trim structureis formed.

[0006] Incidentally, in recent years, some requests for improvements aremade with respect to manufacturability and performance of the thin filmmagnetic head. As a request from the viewpoint of manufacturability, forexample, it can be provided to simplify manufacturing processes so as toshorten manufacturing time. Additionally, as a request from theviewpoint of performance, for example, it can be provided to extremelymicrify the width of the trim structure (pole width) to the order ofsubmicrons (for example, no more than about 0.5 μm) so as to increasethe track density of the recording medium in order to achieve highrecording density.

[0007] However, conventionally, there are problems that it is difficultto shorten the manufacturing time because a lot of manufacturingprocesses are necessary for manufacturing the thin film magnetic head,and that it is difficult to extremely micrify the pole width with highprecision because processing accuracy is not sufficient at the time ofetching the write gap layer and the bottom pole in a self-alignedmanner.

SUMMARY OF THE INVENTION

[0008] The invention has been achieved in consideration of the problems.It is a first object of the invention to provide a thin film magnetichead capable of shortening the manufacturing time and a method ofmanufacturing the same.

[0009] Furthermore, it is a second object of the invention to provide athin film magnetic head capable of extremely micrifying the pole widthwith high precision and a method of manufacturing the same.

[0010] A thin film magnetic head of the invention includes: first andsecond magnetic layers magnetically coupled to each other and havingfirst and second pole tip portions placed so as to face a recordingmedium in conjunction with being in contact with a gap layer and beingopposed to each other as sandwiching the gap layer; a thin film coildisposed in a space between the first and second magnetic layers; and aninsulating layer embedding the thin film coil in the space between thefirst and second magnetic layers. At least the first pole tip portion ismade of a plating film, and the gap layer is constructed of anon-magnetic conductive material.

[0011] A method of manufacturing a thin film magnetic head of theinvention is a method of manufacturing a thin film magnetic headincluding: first and second magnetic layers magnetically coupled to eachother and having first and second pole tip portions placed so as to facea recording medium in conjunction with being in contact with a gap layerand being opposed to each other as sandwiching the gap layer; a thinfilm coil disposed in a space between the first and second magneticlayers; and an insulating layer embedding the thin film coil in thespace between the first and second magnetic layers. The method includes:a step of forming the gap layer with a non-magnetic conductive material;and a step of selectively forming at least the first pole tip portion onthe gap layer by growing a plating film with the gap layer used as anelectrode.

[0012] In the thin film magnetic head of the invention or the method ofmanufacturing the same, after the gap layer is formed with thenon-magnetic conductive material, at least the first pole tip portion isselectively formed on the gap layer by growing the plating film with thegap layer used as an electrode. Unlike the case where the gap layer isformed with a non-magnetic insulating material, a step of separatelyforming an electrode layer necessary for growing the plating film asidefrom the gap layer becomes unnecessary. Therefore, the number of themanufacturing processes is reduced.

[0013] In the method of manufacturing the thin film magnetic head of theinvention, subsequently to selectively etching the gap layer through ionmilling by using at least the first pole tip portion as a mask, thesecond magnetic layer may be selectively etched to a predetermineddepth.

[0014] In the thin film magnetic head of the invention or the method ofmanufacturing the same, it is preferable that a material on which anetching speed through ion milling is within a range extending from beinghigher than 0.5 times to being no more than 2 times of an etching speedon the second magnetic layer is used as the non-magnetic conductivematerial. More specifically, one out of a group consisting of copper,chromium, tantalum, aluminum, gold, niobium, tungsten, ruthenium,molybdenum, beryllium, nickel copper, nickel chromium, nickel phosphorusand beryllium copper, or an alloy including at least the one out of thegroup can be used.

[0015] Furthermore, in the thin film magnetic head of the invention orthe method of manufacturing the same, the first magnetic layer includingthe first pole tip portion may be formed of the plating film as a singlelayer.

[0016] Other and further objects, features and advantages of theinvention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIGS. 1A and 1B are cross sections for explaining a process in amethod of manufacturing a thin film magnetic head according to anembodiment of the invention.

[0018]FIGS. 2A and 2B are cross sections for explaining a processsubsequent to FIGS. 1A and 1B, respectively.

[0019]FIGS. 3A and 3B are cross sections for explaining a processsubsequent to FIGS. 2A and 2B, respectively.

[0020]FIGS. 4A and 4B are cross sections for explaining a processsubsequent to FIGS. 3A and 3B, respectively.

[0021]FIGS. 5A and 5B are cross sections for explaining a processsubsequent to FIGS. 4A and 4B, respectively.

[0022]FIGS. 6A and 6B are cross sections for explaining a processsubsequent to FIGS. 5A and 5B, respectively.

[0023]FIG. 7 is a plan view corresponding to the cross sections shown inFIGS. 2A and 2B.

[0024]FIG. 8 is a plan view corresponding to the cross sections shown inFIGS. 3A and 3B.

[0025]FIG. 9 is a plan view corresponding to the cross sections shown inFIGS. 4A and 4B.

[0026]FIG. 10 is a plan view showing a plane structure of the thin filmmagnetic head according to the embodiment of the invention.

[0027]FIGS. 11A and 11B are cross sections showing a cross-sectionalstructure of a thin film magnetic head as a comparative example of thethin film magnetic head according to the embodiment of the invention.

[0028]FIGS. 12A and 12B are flow charts for explaining mainmanufacturing processes that are necessary for manufacturing the thinfilm magnetic head.

[0029]FIGS. 13A and 13B are diagrams for explaining the influence of theetching speed of the write gap layer in relation to the forming accuracyof the trim structure.

[0030]FIGS. 14A and 14B are cross sections showing a cross-sectionalstructure of a thin film magnetic head as a modification of the thinfilm magnetic head according to the embodiment of the invention.

[0031]FIG. 15 is a plan view showing a plane structure of the thin filmmagnetic head shown in FIGS. 14A and 14B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinbelow, an embodiment of the invention will be described indetail by referring to the drawings.

[0033] <Method of Manufacturing Thin Film Magnetic Head>

[0034] First, referring to FIGS. 1A and 1B to FIGS. 6A and 6B, and FIGS.7 to 9, a method of manufacturing a composite thin film magnetic head as“a method of manufacturing a thin film magnetic head” according to anembodiment of the invention will be described. Incidentally, since “athin film magnetic head” of the invention is embodied by the method ofmanufacturing the thin film magnetic head according to the embodiment,the head will be also described hereinbelow. FIGS. 1A and 1B to FIGS. 6Aand 6B show the method of manufacturing the thin film magnetic head. Ineach pair of drawings, FIGS. 1A to 6A are cross sections each of whichis perpendicular to the air bearing surface, and FIGS. 1B to 6B arecross sections each of which is parallel to the air bearing surface,respectively. FIGS. 7 to 9 show the plane structures corresponding tothe cross-sectional structures shown in FIGS. 2A and 2B to FIGS. 4A and4B, respectively. In FIGS. 7 to 9, only main parts are shown out of theconstituents shown in FIGS. 2A and 2B to FIGS. 4A and 4B.

[0035] In the following description, the X axis direction in each ofFIGS. 1A and 1B to FIGS. 6A and 6B and FIGS. 7 to 9 is described as“width”, the Y axis direction is described as “length”, and the Z axisdirection is described as “thickness (or height)”. The side in the Yaxis direction which is close to an air bearing surface 20 (refer toFIG. 6A) or a side which becomes the air bearing surface 20 in afollowing process is described as “front side (or forward)”, and theopposite side is described as “rear side (or rearward)”. Furthermore, inthe description of FIG. 10 and onward which will be describedhereinafter, the X, Y and Z-axis directions are described in a similarmanner.

[0036] In the method of manufacturing the thin film magnetic headaccording to the embodiment, first of all, as shown in FIGS. 1A and 1B,on a substrate 1 made of attic (Al₂O₃ with TiC) or the like, aninsulating layer 2 made of, for example, alumina is deposited in athickness of about 3.0 μm to 5.0 μm. Subsequently, on the insulatinglayer 2, by using, for example, plating which will be describedhereinafter, a bottom shield layer 3 made of nickel iron alloy (NiFe;hereinbelow, simply called “Permalloy (trade name)”) or the like isselectively formed in a thickness of about 2.0 μm. At the time offorming the bottom shield layer 3, for example, the bottom shield layer3 is made to have a shape in plane as shown in FIG. 10 which will bedescribed hereinafter.

[0037] Subsequently, as shown in FIGS. 1A and 1B, on the bottom shieldlayer 3, a shield gap film 4 made of alumina or the like is formed in athickness of about 0.01 μm to 0.1 μm by, for example, sputtering.Subsequently, on the shield gap film 4, an MR film 5 for constructing anMR device is formed so as to be in a desirably patterned shape byhigh-precision photolithography. Subsequently, by using a material and aforming method similar to those in the case where the shield gap film 4is formed, a shield gap film 6 is formed so as to cover the MR film 5,and thereby the MR film 5 is buried in the shield gap films 4 and 6.

[0038] Subsequently, as shown in FIGS. 1A and 1B, on the shield gap film6, for example, by using a forming method and a forming material similarto those in the case where the bottom shield layer 3 is formed, a bottompole 7 is selectively formed in a thickness of about 2.0 μm to 3.0 μm.At the time of forming the bottom pole 7, for example, the bottom pole 7is made to have a shape in plane as shown in FIG. 10 which will bedescribed hereinafter. Here, the bottom pole 7 corresponds to an exampleof “second magnetic layer” in the invention.

[0039] Subsequently, on the bottom pole 7, by applying a material whichis fluidized when being heated, for example, an organic insulatingmaterial such as photoresist, a photoresist film is selectively formed.Next, a heat treatment is conducted on the photoresist film at atemperature of about 200° C. to 250° C. By the heat treatment, as shownin FIGS. 2A and 2B and FIG. 7, an insulating layer 8 is selectivelyformed. The surface in the vicinity of the edge of the insulating layer8 forms a slope which is rounded in accordance with the fluidity ofphotoresist at the time of the heat treatment. At the time of formingthe insulating layer 8, the disposing region of the insulating layer 8is made to correspond to a disposing region of a thin film coil 9 whichwill be described hereinafter.

[0040] Subsequently, as shown in FIGS. 2A and 2B and FIG. 7, on theinsulating layer 8, the thin film coil 9 for an inductive recording headmade of copper (Cu) or the like is selectively formed in a thickness ofabout 1.5 μm by, for example, electrolytic plating. At the time offorming the thin film coil 9, for example, the thin film coil 9 is madeto have a winding structure in a spiral shape as shown in FIG. 7.

[0041] Subsequently, as shown in FIGS. 2A and 2B and FIG. 7, by aforming material and a forming method similar to those in the case wherethe insulating layer 8 is formed, an insulating layer 10 is selectivelyformed so as to cover the insulating layer 8, the thin film coil 9 andthe peripheral region thereof. The spacing between each turns of thethin film coil 9 is filled up with the insulating layer 10 so as tobridge the gap. At the time of forming the insulating layer 10, forexample, the insulating layer 10 is formed so that the top face of thethin film coil 9 is exposed.

[0042] Subsequently, as shown in FIGS. 2A and 2B and FIG. 7, by aforming material and a forming method similar to those in the case wherethe insulating layer 8 is formed, an insulating layer 11 is selectivelyformed on the insulating layer 10. At the time of forming the insulatinglayer 11, for example, the insulating layer 11 is formed so as to coverat least the thin film coil 9 and so that its front end recedes rearwardof the front end of the insulating layer 10. The insulating layers 8, 10and 11 electrically isolate the thin film coil 9 from its periphery.Here, a group of the insulating layers 8, 10 and 11 corresponds to anexample of “insulating layer” in the invention.

[0043] Subsequently, as shown in FIGS. 2A and 2B and FIG. 7, bysputtering or the like, a write gap layer 12 is formed in a thickness ofabout 0.1 μm to 0.3 μm so as to cover the entire surface. At the time offorming the write gap layer 12, an opening 12K is formed for connectingthe bottom pole 7 with a top pole 13 (refer to FIG. 3) which will beformed in a following process. As a forming material of the write gaplayer 12, for example, a non-magnetic conductive material which has anion milling speed E1 within the range from nearly half (exclusive) of anetching speed E2 on the bottom pole 7 to two times of the etching speedE2 (0.5×E2<E1≦2.0≦E2) is used. More specifically, for example, onematerial out of a group composed of copper, chromium (Cr), tantalum(Ta), aluminum (Al), gold (Au), niobium (Nb), tungsten (W), ruthenium(Ru), molybdenum (Mo), beryllium (Be), nickel copper (NiCu), nickelchromium (NiCr), nickel phosphorus (NiP) and beryllium copper (BeCu), oran alloy including at least one material out of the group is used.Especially, it is more preferable that tantalum, ruthenium or the like,which has the ion milling speed E1 almost equal to the etching speed E2(E1≈E2), is used as the forming material of the write gap layer 12. Thewrite gap layer 12 functions as a gap in order to generate a signalmagnetic flux for writing between the bottom pole 7 and the top pole 13,and functions as a seed layer (electrode) for forming the top pole 13through plating in a following process. Here, the write gap layer 12corresponds to an example of “gap layer” in the invention.

[0044] Subsequently, a photoresist is applied on the entire surface soas to form a photoresist film. After that, by patterning the photoresistfilm through a high-precision photolithography process, a framework(frame pattern; not shown in the drawings) for forming the top pole 13is selectively formed.

[0045] Subsequently, by using the frame pattern which is formed in theprevious process, and by using the write gap layer 12 as the seed layer,a plating film is grown. Consequently, as shown in FIGS. 3A and 3B andFIG. 8, in a region extending from a side (left side in FIG. 3A, bottomside in FIG. 8) which will be the air bearing surface 20 in a followingprocess to the opening 12K, the top pole 13 is selectively formed in athickness of about 0.3 μm to 6.0 μm. The top pole 13 is made of amaterial having a high saturation magnetic flux density includingnickel, cobalt (Co) or iron (Fe), for example, Permalloy, cobalt iron(CoFe), nickel cobalt iron (CoFeNi) or the like. At the time of formingthe top pole 13, for example, as shown in FIG. 8, the top pole 13 ismade to include a tip portion 13A and a yoke portion 13B in accordancewith the order from the side which will be the air bearing surface 20 inthe following process. The tip portion 13A has an extremely minuteuniform width W1 (for example, W1≈0.3 μm) for defining the recordingtrack width, and the yoke portion 13B has a width wider than the widthof the tip portion 13A. The structural characteristics of the top pole13 will be described hereinafter. The top pole 13 is magneticallycoupled to the bottom pole 7 in the opening 12K, so that a propagationpath of the magnetic flux (magnetic path) is formed with the bottom pole7 and the top pole 13. Here, the top pole 13 corresponds to an exampleof “first magnetic layer” in the invention and the tip portion 13Acorresponds to an example of “first pole tip portion” in the invention.

[0046] Subsequently, as shown in FIGS. 4A and 4B and FIG. 9, by usingthe top pole 13 as a mask, part of the write gap layer 12 is etched andremoved except for the part corresponding to the disposing region of thetop pole 13, through ion milling or the like.

[0047] Subsequently, following the etching process on the write gaplayer 12, as shown in FIGS. 4A and 4B and FIG. 9, the bottom pole 7 andthe like around the top pole 13 are etched and removed in a similarmanner. At the time of etching the bottom pole 7 and the like, forexample, the bottom pole 7 is dug down until a depth of etching reachesabout 0.5 μm from the surface of the write gap layer 12. Thereby, a trimstructure 100 is formed. The trim structure 100 is constituted of thetip portion 13A (width W1) in the top pole 13, a portion (portion 7P;width W2) corresponding to the tip portion 13A in the bottom pole 7 anda portion (width W3) sandwiched between the tip portion 13A and theportion 7P in the write gap layer 12. Each of these constituents hasalmost the same width as each other (W1=W2=W3). Here, the portion 7Pcorresponds to an example of “second pole tip portion” in the invention.

[0048] Subsequently, as shown in FIGS. 5A and 5B, an overcoat layer 14made of an inorganic insulating material such as alumina or the like isformed in a thickness of about 20 μm to 40 μm so as to cover the entiresurface.

[0049] Finally, as shown in FIGS. 6A and 6B, by machining process andpolishing step, the air bearing surface 20 of the recording head and thereproducing head is formed, and thereby the thin film magnetic head iscompleted.

[0050] <Structure of Thin Film Magnetic Head>

[0051] Referring now to FIG. 10, the plane configuration of the thinfilm magnetic head according to the embodiment will be described.

[0052]FIG. 10 schematically shows the plane configuration of the thinfilm magnetic head manufactured by the method of manufacturing the thinfilm magnetic head according to the embodiment. Incidentally, in FIG.10, the substrate 1, the insulating layer 2, the shield gap films 4 and6 and the overcoat layer 14 are omitted. Furthermore, only part of theoutermost region is shown with respect to the thin film coil 9. FIG. 6Acorresponds to a cross section taken along line VIA-VIA in FIG. 10.

[0053] The position of the front end of the insulating layer 10 is theposition which is a reference at the time of determining the throatheight (TH), that is, the throat height zero position (TH0 position).The throat height (TH) is one of the factors which determine theperformance of the recording head. The throat height is specified as alength from the position (TH0 position) of the front end of theinsulating layer 10 to the air bearing surface 20.

[0054] The top pole 13 is, as described above, disposed on the write gaplayer 12. For example, the top pole 13 includes the tip portion 13Ahaving the extremely minute uniform width W1 for defining the recordingtrack width and the yoke portion 13B, which is magnetically coupled tothe tip portion 13A, for accommodating the magnetic flux generated bythe thin film coil 9 in accordance with the order from the air bearingsurface 20. The tip portion 13A, for example, has a rectangular shape inplane. The width of the yoke portion 13B is wider than the width W1 ofthe tip portion 13A. For example, the width of the yoke portion 13B isalmost uniform in the rear part, and is gradually narrowed toward theair bearing surface 20 in the front part.

[0055] <Operation of Thin Film Magnetic Head>

[0056] Referring now to FIGS. 6A and 6B and FIG. 10, the operation ofthe thin film magnetic head will be described.

[0057] In the thin film magnetic head, when current is passed to thethin film coil 9 via the external circuit (not shown) at the time ofrecording information, magnetic flux is accordingly generated. Themagnetic flux generated at this time is accommodated in the yoke portion13B of the top pole 13, and afterward propagates from the yoke portion13B to the tip portion 13A. The magnetic flux propagated to the tipportion 13A further reaches the front end part of the tip portion 13A onthe air bearing surface 20 side. The magnetic flux reached the front endpart of the tip portion 13A generates a signal magnetic flux forrecording on the outside near the write gap layer 12. By the signalmagnetic flux, the recording medium is partially magnetized so as torecord information onto the recording medium.

[0058] On the other hand, at the time of reproducing information, asense current is passed to the MR film 5. A resistance value of the MRfilm 5 changes in accordance with a reproducing signal magnetic fieldfrom the magnetic recording medium. By detecting the change inresistance on the basis of a change in the sense current, informationrecorded on the magnetic recording medium can be read out.

[0059] <Action and Effects of Embodiment>

[0060] Referring now to FIGS. 6A, 6B, 11A, 11B, 12A and 12B, action andeffects of the embodiment will be described. FIGS. 11A and 11B show across-sectional structure of a conventional thin film magnetic head as acomparative example with respect to the thin film magnetic headaccording to the embodiment, corresponding to FIGS. 6A and 6B. FIGS. 12Aand 12B are flow charts for explaining main manufacturing processes thatare necessary for manufacturing a thin film magnetic head. FIG. 12Ashows the flow chart with regard to the thin film magnetic head of thecomparative example, and FIG. 12B shows the flow chart with regard tothe thin film magnetic head of the embodiment, respectively. FIGS. 12Aand 12B show the main manufacturing processes from forming a write gaplayer to forming a trim structure. In the drawings, it is shown thatprocesses linked by a broken line are in correspondence with each other.Incidentally, with regard to the thin film magnetic head shown in FIGS.11A and 11B, the structure except points which will be describedhereinbelow is similar to the structure of the thin film magnetic headshown in FIGS. 6A and 6B.

[0061] In the embodiment, after the write gap layer 12 is formed of anon-magnetic conductive material, using the write gap layer 12 as a seedlayer, the top pole 13 is formed on the write gap layer 12 throughplating process. The manufacturing time of the thin film magnetic headcan be therefore shortened for reasons as follow.

[0062] More specifically, in the comparative example (FIGS. 11A and11B), a write gap layer 22 is formed of a non-magnetic insulatingmaterial such as alumina or the like. In such a case, the top pole 13cannot be formed directly on the write gap layer 22 by plating process,and therefore a process of newly forming a seed layer as an electrodefilm necessary for performing the plating process on the write gap layer22 is necessary. Additionally, after forming the top pole 13 on the seedlayer by plating process, a process of selectively removing unnecessarypart of the newly formed seed layer except the part corresponding to theforming region of the top pole 13 by etching process is, furthermore,necessary. Therefore, the number of the manufacturing processesnecessary in the comparative example is seven in total (refer to FIG.12A). To be more specific, the processes are of “forming the write gaplayer (S101)”, “forming the seed layer (S102)”, “forming the framepattern (S103)”, “plating process (forming the top pole; S104)”,“selectively removing the seed layer (S105)”, “selectively removing thewrite gap layer (S106)” and “selectively removing the bottom pole(forming the trim structure; S107)”.

[0063] In contrast to this, in the embodiment (refer to FIGS. 6A and6B), since the write gap layer 12 constructed of the non-magneticconductive material also functions as the seed layer, the process ofnewly forming the seed layer and the process of selectively removing thenewly formed seed layer, which are necessary in the comparative example,become unnecessary. Therefore, the manufacturing processes necessary inthe embodiment are of “forming the write gap layer 12 (S201)”, “formingthe frame pattern (S202)”, “plating process (forming the top pole 13;S203)”, “selectively removing the write gap layer 12 (S204)” and“selectively removing the bottom pole 7 (forming the trim structure 100;S205)”. That is, the number of the processes is five in total, andreduced by two from the number in the comparative example (refer toFIGS. 12A and 12B). Consequently, the manufacturing time of the thinfilm magnetic head is shortened as much as the reduced manufacturingprocesses. Moreover, in the embodiment, since the process of“selectively removing the write gap layer 12 (S204)” and the process of“selectively removing the bottom pole 7 (S205)” can be performedcontinuously as if they were one process, the manufacturing time isshortened in this point as well.

[0064] Furthermore, in the embodiment, as a result of forming the writegap layer 12 by using the non-magnetic conductive material, not only isthe manufacturing time shortened as described above, but also the polewidth can be extremely narrowed with high precision. In the followingdescription, referring to FIGS. 13A and 13B, this point will beexplained. FIGS. 13A and 13B are diagrams for explaining the influenceof the ion milling speed E1 of the write gap layer 12 in relation to theforming accuracy of the trim structure 100, corresponding to FIG. 6B.

[0065] Generally, it is known that the etching speed by ion milling ofthe non-magnetic conductive materials such as copper that are listed asa forming material of the write gap layer 12 in the above-described“method of manufacturing the thin film magnetic head” is higher thanthat of the non-magnetic insulating material such as alumina. In thecomparative example (refer to FIGS. 11A and 11B) of forming the writegap layer 12 by using the non-magnetic insulating material, whenselectively etching the write gap layer 12 and the bottom pole 7 throughion milling by using the top pole 13 as a mask in order to form the trimstructure 100, the ion milling speed E1 of the write gap layer 12 islow, and the etched amount is reduced. Consequently, the processed widthW3 of the write gap layer 12 becomes wider than the width W1 of the tipportion 13A (W3>W1), and the processed width W2 of the portion 7P alsobecomes wider than the width W1 of the tip portion 13A (W2>W1). That isto say, it becomes difficult to extremely narrow the pole width withhigh precision (refer to FIG. 13A).

[0066] In contrast to this, in the embodiment of forming the write gaplayer 12 by using the non-magnetic conductive material, the ion millingspeed E1 of the write gap layer 12 is high, approaching the etchingspeed of the top pole 13 and the bottom pole 7. As a result, unlike thecomparative example, as shown in FIG. 6B, both of the processed width W3of the write gap layer 12 and the processed width W2 of the bottom pole7 can be made to coincide with the width W1 of the tip portion 13A(W1=W2=W3), and thereby the pole width can be extremely narrowed withhigh precision.

[0067] This is evident from results shown in Table 1. Table 1 shows theexperimental results on the processing accuracy of the pole width. Theupper row shows those of the comparative example, and the lower rowshows those of the embodiment, respectively. Here, an average pole width(μm), a standard deviation (μm) of the pole width and a difference(width difference=W2−W1; μm) between the processed width W1 of the tipportion 13A and the processed width W2 of the portion 7P are shown asexperimental items. TABLE 1 average pole width standard deviation widthdifference (μm) (μm) (μm) 0.325 0.031 0.05 0.316 0.017 0.01

[0068] As is evident from the results shown in Table 1, in theembodiment, a value smaller than that in the comparative example isobtained with respect to any of the experimental items. Morespecifically, judging from the average pole width being smaller, it hasbeen shown that the pole width can be more extremely narrowed.Additionally, judging from the standard deviation of the pole width andthe width difference being smaller, it has been shown that variation inthe pole width is little, and that the trim structure 100 can be formedwith higher precision. On investigation of the ion milling speed E1 ofthe write gap layer 12, in the comparative example, the ion millingspeed E1 is half of the etching speed E2 of the bottom pole 7. Incontrast to this, in the embodiment, the ion milling speed E1 is betweennearly half (exclusive) and about two times of the etching speed E2.Particularly, it is more preferable that the ion milling speed E1 isalmost equal to the etching speed E2.

[0069] Incidentally, when the ion milling speed E1 of the write gaplayer 12 is higher than about two times of the etching speed E2 of thebottom pole 7, as shown in FIG. 13B, the write gap layer 12 isexcessively etched. Consequently, the processed width W3 of the writegap layer 12 becomes excessively narrower than the width W1 of the tipportion 13A and the width W2 of the portion 7P. In such a case, theamount of the leakage flux generated between the tip portion 13A and theportion 7P increases, thereby causing a possibility of being short ofthe signal magnetic flux. Therefore, it is rather undesirable that theion milling speed E1 is much too high. On the basis of the descriptionup to this point, the ion milling speed E1 of the write gap layer 12 ispreferably within the above-indicated range. Particularly, it is morepreferable that the ion milling speed E1 is almost equal to the etchingspeed E2 of the bottom pole 7.

[0070] Furthermore, since the ion milling is used in the embodiment as aforming technique of the trim structure 100, the embodiment has anadvantage from the viewpoint of making it easy to manufacture the thinfilm magnetic head. More specifically, as mentioned above, when thewrite gap layer 12 constructed of the non-magnetic insulating materialis etched by ion milling, the ion milling speed E1 of the write gaplayer 12 is low, therefore resulting in the prolonged manufacturingtime. In this case, in order to make the ion milling speed E1 high forthe purpose of shortening the manufacturing time, it is conceivable asmeans for processing the write gap layer 12 to utilize a physical andchemical etching action, for example, by using a reactive ion beametching (RIBE) as an etching technique. However, in the case where theRIBE is used, since operations such as preparing an etching gas, settingan etching temperature and the like is necessary in order to ensure thechemical etching action, the etching process becomes complicated.Contrastively, since the ion milling utilized in the embodiment, unlikethe RIBE, does not need the operations such as preparing the etching gasand the like, the etching process is simplified.

[0071] <Modifications of Embodiment>

[0072] Incidentally, although the write gap layer 12 is, as shown inFIG. 7, formed on the entire surface and the top pole 13 is formed byselectively performing the plating process with the frame pattern in theembodiment, the invention is not always limited to this. For example,the write gap layer 12 may be selectively formed only in a region wherethe top pole 13 will be formed.

[0073] Furthermore, although the top pole 13 consisting of a singleplating film is formed in the embodiment, the invention is not alwayslimited to this. As shown in FIGS. 14A and 14B and FIG. 15, a top pole113 consisting of a plurality of parts may be formed. FIG. 15 shows aplane structure of a thin film magnetic head as a modification of theembodiment. FIG. 14A shows a cross-sectional structure taken along lineXIVA-XIVA shown in FIG. 15. FIGS. 14A and 14B and FIG. 15 correspond toFIGS. 6A and 6B and FIG. 10, respectively. In passing, except for pointswhich will be explained on the thin film magnetic head in the followingdescription, the construction, the forming material of each constituent,the forming method, the structural characteristics and the like aresimilar to those in the case of the above embodiment.

[0074] In the thin film magnetic head, for example, a write gap layer112 is disposed on the bottom pole 7. The top pole 113 includes and isconstructed of a top pole tip 113A disposed on the write gap layer 112,a connection portion 113B and a top yoke 113C overlapping with the toppole tip 113A and the connection portion 113B. The top pole 113 ismagnetically coupled to the bottom pole 7 through an opening 112K. Thetop pole tip 113A includes a tip portion 113A1 having the uniform widthW1 in correspondence with the tip portion 13A and a rear end portion113A2 of a width wider than the width W1 of the tip portion 113A1. Thetop yoke 113C includes a front portion of a width wider than the widthof the rear end portion 113A2 and a rear portion of a width still widerthan the width of the front portion. The thin film coil 109 is embeddedin a space surrounded by the write gap layer 112 and the top pole 113,and the space is filled with an insulating layer 115 made of alumina orthe like. The front-end position of the insulating layer 115 correspondsto the TH0 position.

[0075] At the time of manufacturing the thin film magnetic head, forexample, to begin with, the write gap layer 112 made of a non-magneticconductive material is formed on the bottom pole 7. After that, the toppole tip 113A and the connection portion 113B is selectively formedthrough plating process by using the write gap layer 112 as a seed layerin a manner similar to the case where the top pole 13 is formed in theabove embodiment. Subsequently, after the thin film coil 109 is formedon the write gap layer 112 in the space between the top pole tip 113Aand the connection portion 113B, the alumina layer is formed so as tocover at least the space. Subsequently, after the entire surface ispolished to be planarized by CMP (Chemical Mechanical Polishing) methodor the like until at least both of the top pole tip 113A and theconnection portion 113B are exposed, the top yoke 113C is formed on theplanarized surface. In passing, as a forming method of the top yoke113C, the plating process may be used as is the case with the top poletip 113A and the like. And, moreover, other film-forming technique maybe used.

[0076] In the thin film magnetic head of such construction or the methodof manufacturing the same, effects similar to those in the case of theabove embodiment can be also achieved. Here, the write gap layer 112corresponds to an example of “gap layer” in the invention, the top pole113 corresponds to an example of “first magnetic layer” in theinvention, and the tip portion 113A1 corresponds to an example of “firstpole tip portion” in the invention.

[0077] Although the invention has been described above by naming theembodiments, the invention is not limited to the above embodiments butcan be variously modified. The details of the construction of the thinfilm magnetic head and the manufacturing method which have beendescribed in the above embodiments are not necessarily limited to thosedescribed in the above embodiments, but can be freely changed as far asit can be attained to shorten the manufacturing time and to make thepole width extremely narrow with high precision by forming the write gaplayer 12 with the non-magnetic conductive material.

[0078] Furthermore, for example, in the above embodiments, the casewhere the invention is applied to the composite thin film magnetic headhas been described. However, the invention is not necessarily limited tothis, but can be also applied to a recording-only thin film magnetichead having an inductive magnetic transducer for writing, a thin filmmagnetic head having an inductive magnetic transducer for recording andreproducing or a thin film magnetic head of a structure in which anelement for writing and an element for reading are laminated in oppositeorder.

[0079] As described above, according to the thin film magnetic head orthe method of manufacturing the thin film magnetic head of theinvention, after forming the gap layer with the non-magnetic conductivematerial, at least the first pole tip portion is formed on the gap layerby growing the plating film with the gap layer used as an electrode.Consequently, the process of newly forming the electrode layer for theplating process and the process of selectively removing the newly formedelectrode layer become unnecessary unlike the conventional case wherethe gap layer is formed by using the non-magnetic insulating material.Therefore, the manufacturing time of the thin film magnetic head can beshortened because the number of manufacturing processes is reduced.

[0080] Especially, according to the method of manufacturing the thinfilm magnetic head of one aspect of the invention, by using at least thefirst pole tip portion as a mask, the gap layer is selectively removedby ion milling, and subsequently the second magnetic layer isselectively etched to a predetermined depth. Consequently, the etchingspeed of the gap layer becomes higher than that of the case where thegap layer constructed of the non-magnetic insulating material is etched,thereby the manufacturing time of the thin film magnetic head can betherefore shortened. Better still, the pole width can be extremelynarrowed with high precision because the etching amount of the gap layeris made appropriate.

[0081] Obviously many modifications and variations of the presentinvention are possible in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed is:
 1. A thin film magnetic head comprising: first andsecond magnetic layers magnetically coupled to each other and havingfirst and second pole tip portions placed so as to face a recordingmedium in conjunction with being in contact with a gap layer and beingopposed to each other as sandwiching the gap layer; a thin film coildisposed in a space between the first and second magnetic layers; and aninsulating layer embedding the thin film coil in the space between thefirst and second magnetic layers, wherein: at least the first pole tipportion is made of a plating film; and the gap layer is constructed of anon-magnetic conductive material.
 2. A thin film magnetic head accordingto claim 1, wherein the gap layer is constructed of the non-magneticconductive material on which an etching speed through ion milling iswithin a range extending from being higher than 0.5 times to being nomore than 2 times of an etching speed on the second magnetic layer.
 3. Athin film magnetic head according to claim 1, wherein the gap layer isconstructed of one out of a group consisting of copper (Cu), chromium(Cr), tantalum (Ta), aluminum (Al), gold (Au), niobium (Nb), tungsten(W), ruthenium (Ru), molybdenum (Mo), beryllium (Be), nickel copper(NiCu), nickel chromium (NiCr), nickel phosphorus (NiP) and berylliumcopper (BeCu), or an alloy including at least the one out of the group.4. A thin film magnetic head according to claim 2, wherein the gap layeris constructed of one out of a group consisting of copper (Cu), chromium(Cr), tantalum (Ta), aluminum (Al), gold (Au), niobium (Nb), tungsten(W), ruthenium (Ru), molybdenum (Mo), beryllium (Be), nickel copper(NiCu), nickel chromium (NiCr), nickel phosphorus (NiP) and berylliumcopper (BeCu), or an alloy including at least the one out of the group.5. A thin film magnetic head according to claim 1, wherein the firstmagnetic layer including the first pole tip portion is constructed ofthe plating film as a single layer.
 6. A thin film magnetic headaccording to claim 2, wherein the first magnetic layer including thefirst pole tip portion is constructed of the plating film as a singlelayer.
 7. A thin film magnetic head according to claim 3, wherein thefirst magnetic layer including the first pole tip portion is constructedof the plating film as a single layer.
 8. A thin film magnetic headaccording to claim 4, wherein the first magnetic layer including thefirst pole tip portion is constructed of the plating film as a singlelayer.
 9. A method of manufacturing a thin film magnetic headcomprising: first and second magnetic layers magnetically coupled toeach other and having first and second pole tip portions placed so as toface a recording medium in conjunction with being in contact with a gaplayer and being opposed to each other as sandwiching the gap layer; athin film coil disposed in a space between the first and second magneticlayers; and an insulating layer embedding the thin film coil in thespace between the first and second magnetic layers, wherein the methodcomprises: a step of forming the gap layer with a non-magneticconductive material; and a step of selectively forming at least thefirst pole tip portion on the gap layer by growing a plating film withthe gap layer used as an electrode.
 10. A method of manufacturing a thinfilm magnetic head according to claim 9, further including a step ofselectively etching the gap layer through ion milling by using at leastthe first pole tip portion as a mask and, subsequently, selectivelyetching the second magnetic layer to a predetermined depth.
 11. A methodof manufacturing a thin film magnetic head according to claim 9, whereina material on which an etching speed through ion milling is within arange extending from being higher than 0.5 times to being no more than 2times of an etching speed on the second magnetic layer is used as thenon-magnetic conductive material.
 12. A method of manufacturing a thinfilm magnetic head according to claim 10, wherein a material on which anetching speed through ion milling is within a range extending from beinghigher than 0.5 times to being no more than 2 times of an etching speedon the second magnetic layer is used as the non-magnetic conductivematerial.
 13. A method of manufacturing a thin film magnetic headaccording to claim 9, wherein one out of a group consisting of copper,chromium, tantalum, aluminum, gold, niobium, tungsten, ruthenium,molybdenum, beryllium, nickel copper, nickel chromium, nickel phosphorusand beryllium copper, or an alloy including at least the one out of thegroup is used as the non-magnetic conductive material.
 14. A method ofmanufacturing a thin film magnetic head according to claim 10, whereinone out of a group consisting of copper, chromium, tantalum, aluminum,gold, niobium, tungsten, ruthenium, molybdenum, beryllium, nickelcopper, nickel chromium, nickel phosphorus and beryllium copper, or analloy including at least the one out of the group is used as thenon-magnetic conductive material.
 15. A method of manufacturing a thinfilm magnetic head according to claim 11, wherein one out of a groupconsisting of copper, chromium, tantalum, aluminum, gold, niobium,tungsten, ruthenium, molybdenum, beryllium, nickel copper, nickelchromium, nickel phosphorus and beryllium copper, or an alloy includingat least the one out of the group is used as the non-magnetic conductivematerial.
 16. A method of manufacturing a thin film magnetic headaccording to claim 12, wherein one out of a group consisting of copper,chromium, tantalum, aluminum, gold, niobium, tungsten, ruthenium,molybdenum, beryllium, nickel copper, nickel chromium, nickel phosphorusand beryllium copper, or an alloy including at least the one out of thegroup is used as the non-magnetic conductive material.
 17. A method ofmanufacturing a thin film magnetic head according to claim 9, whereinthe first magnetic layer including the first pole tip portion is formedof the plating film as a single layer.
 18. A method of manufacturing athin film magnetic head according to claim 10, wherein the firstmagnetic layer including the first pole tip portion is formed of theplating film as a single layer.
 19. A method of manufacturing a thinfilm magnetic head according to claim 11, wherein the first magneticlayer including the first pole tip portion is formed of the plating filmas a single layer.
 20. A method of manufacturing a thin film magnetichead according to claim 12, wherein the first magnetic layer includingthe first pole tip portion is formed of the plating film as a singlelayer.
 21. A method of manufacturing a thin film magnetic head accordingto claim 13, wherein the first magnetic layer including the first poletip portion is formed of the plating film as a single layer.
 22. Amethod of manufacturing a thin film magnetic head according to claim 14,wherein the first magnetic layer including the first pole tip portion isformed of the plating film as a single layer.
 23. A method ofmanufacturing a thin film magnetic head according to claim 15, whereinthe first magnetic layer including the first pole tip portion is formedof the plating film as a single layer.
 24. A method of manufacturing athin film magnetic head according to claim 16, wherein the firstmagnetic layer including the first pole tip portion is formed of theplating film as a single layer.